1. Field of the Invention
The present invention relates to the production of fibrous products. More particularly, the present invention relates to the production of fiberglass products which incorporate a filler, preferably a clay filler.
2. Description of the Related Art
Fiberglass products are commonly produced by melting the glass and then fiberizing the molten liquid. Primary fibers so produced are attenuated into smaller diameter fibers of finite length which typically are deposited onto a moving support or collection surface to form a mass or layer of uniformly distributed, intertwined fibers. Liquid binder is sprayed on the fibers as they move toward the support. The mass or layer of fibers is subsequently transported into an oven in which the binder is set or cured.
The properties of the fibrous products produced in this manner are based upon the properties of the glass fibers, and the compositions of the glasses themselves. It would at times be beneficial to modify the products in order to enhance certain properties and/or reduce costs. A major problem encountered in introducing additive materials or extenders is the difficulty in uniformly distributing them throughout the fibrous matrix. If liquid additives are not sticky, they may be difficult to adhere to the fibers when sprayed onto the fibers as they move toward the collection surface. If liquid additives are sprayed onto an already formed fibrous mass, it is difficult to uniformly disperse them throughout the mass. It is even more difficult to add solid additives to a layer or a mass of collected fibers so as to uniformly penetrate and become dispersed throughout the mass. Indeed, if the particular additive or extender desired is available only in solid form, the present state of the art of introducing it to the fibrous product dictates against such addition.
U.S. Pat. No. 5,123,949 discloses a particular method of adding solid additives to a fiber product. A heat curable liquid binder is sprayed at the same time as the particle additives onto the moving fibers, from a point inside the fiber veil. The specific extenders noted as useful include volcanic ash, expanded perlite, or vermiculite. The size of the extender particles generally ranges from one-eighth to one-quarter inch. Such extenders may typically be present in the product up to 70% by weight, with 40% being a commercially practical maximum amount, as disclosed in the patent.
The addition of fillers or extenders, as well as other additives to the binder solution, is known in the art. For example, see U.S. Pat. No. 5,661,213, which lists many different types of additives for a curable aqueous composition used as a binder, including fillers. The use of large amounts of fillers or extenders in binder solutions, if the filler or extender were to not interfere with the appearance or function of the binder, would enable the use of binders in a more cost effective manner. While the concept of adding fillers to a binder solution has been suggested, particular fillers and their amounts, and/or particular effective methods of adding the filler to the binder solution have not heretofore been contemplated. If such fillers or extenders also enhanced certain properties of the fiberglass product, not only would the economics of its use be desirable, but product advantages would also be realized. The use of such fillers or extenders in conjunction with binder compositions would be greatly desirable.
Accordingly, an objective of the present invention is to provide an extended binder system for fiberglass which enables the use of the binder in a more cost effective manner, and also avoids substantial problems in the application of the binder containing the filler or extender.
Yet another object of the present invention is to provide an extended binder which also enhances the physical characteristics of the fiberglass product.
These and other objects of the present invention will become apparent to the skilled artisan upon a reading of the following specification and the claims appended hereto.
In accordance with the foregoing objectives, the present invention provides one with a fiberglass binder comprising an aqueous solution of a polycarboxy polymer, a polyol and at least 30 weight percent of a filler material, preferably a clay filler material. The clay filler preferably comprises bentonite or kaolin. The filler material is suspended in the fiberglass binder aqueous solution, with the average size of the filler material particles being about 3 xcexcm or less. Such a stable suspension is important to the success of extending the binder.
Among other factors, the present invention is based upon the discovery that the use of a filler material such as clay can be stably suspended in a binder aqueous solution comprised of a polycarboxy polymer and a polyol, in amounts of at least 30 weight percent, thereby enabling a more cost effective use of the fiberglass binder. The filler material is suspended in the solution by employing particles having an average size of about 3 xcexcm or less, thereby leading to a stable suspension. Application of the binder using conventional methods is therefore appropriate. The final product has also been found to exhibit enhanced toughness, and thus better performance, upon suspending the filler, especially clay, in the binder solution.